Cooling package assembly for work vehicles

ABSTRACT

A cooling package assembly for a work vehicle. A plurality of heat exchangers cooperate with one another to define an interior of a cooling box. Single pass airflow is pushed across the heat exchangers. In one embodiment, the heat exchangers cooperate with one another to define a v-shape.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/471,014 filed Apr. 1, 2011, entitled “Cooling Package Assembly ForWork Vehicles” and is also related to U.S. application 61/470,996entitled “Pusher Airflow for Work Vehicle Cooling System”, U.S.application 61/471,025 entitled “Debris Passageway for Work VehicleCooling Package”, U.S. application 61/471,040 entitled “Controller forWork Vehicle Cooling Package”, U.S. application 61/471,050 entitled “AirMover Reversing For Work Vehicle Cooling Package”, U.S. application61/471,063 entitled “Control Method for Primary and Supplemental CoolingSystems for a Work Vehicle”, and U.S. application 61/471,075 entitled“Method for Determining When Cooling System is Restricted”, which havebeen filed concurrently with the present application.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to drawing in ambient air into agriculturalmachines such as combine harvesters and windrowers for cooling and otherpurposes.

2. Background

Current harvesting vehicles have issues with their coolingsystems/packages. Most bring in high volumes of air into the coolingpackages from the sides of the vehicles. Radiator screens are well knownin the art. They are used to filter debris from an ambient air stream asit is drawn into the engine compartment. Due to cross-winds and the highvolume of light, small trash from harvesting operations surrounding theharvesting equipment, the intake screens of these vehicles becomeplugged. Many agricultural vehicles use various devices to remove debrisfrom the plugged radiator screens.

U.S. Pat. No. 5,944,603 discloses a sealing apparatus for a rotatableair inlet screen of an agricultural vehicle. The screen assembly 20 ispositioned over the air inlet housing 22 and includes a rotatable member24, screens 26 and 28, and cleaning assembly 30. The radiator fan 18,driven by the engine 14, draws air through radiator 16. The rotatablemember 24 is unpowered and therefore does not push air into the airinlet housing or across the radiator 18. The radiator fan 18 inducesairflow downward through screens 26, 28 and then the direction ofairflow is changed in order for the airflow to pass through the radiator16. The radiator fan 18 also induces rotation of rotatable member 24 andscreen assembly 20 which results in a negative pressure difference.

Agricultural vehicles typically utilize stacked or multiple pass heatexchangers or cores such as A/C, engine radiators, charge air coolers,hydraulic coolers, condensers, etc. This reduces the cooling capacity ofthe downstream oil coolers and radiators as well as significantlyincreases the possibility of plugging intake screens.

However, a design which uses an air mover to push air from the top ofthe vehicle, where the air is cleaner compared to the sides of thevehicle, allows for the cleanest possible area for intake air. This alsoallows for a larger intake area and therefore a much lower intakeairflow velocity. What is needed is a pusher air mover preferablylocated between the screen area and the heat exchangers that allows coolairflow to be pushed into the cooling package across the heat exchangersarranged in a configuration to permit single pass of fresh airflowacross each heat exchanger to increase efficiency and reduce pluggingduring normal operation. The air mover may also be reversible at optimaltimes to generate airflow in the reverse direction to remove debris suchas accumulated soil and small plant materials surrounding the screenarea during a cleaning operation.

OVERVIEW OF THE INVENTION

The invention is directed to a cooling package assembly for a workvehicle. A plurality of heat exchangers cooperate with one another todefine an interior of a cooling box. Single pass airflow is pushedacross the heat exchangers. In one embodiment, the heat exchangerscooperate with one another to define a v-shape.

In one embodiment, the invention is directed to a cooling system for awork vehicle. The cooling system has a plurality of heat exchangerscooperating with one another wherein upstream faces at least partiallydefine a substantially closed interior of a cooling box. An air moverpushes a plurality of single pass airflows across the upstream faces ofeach of the heat exchangers. The air mover is operative to push ambientair downward through the cooling box from overhead of the work vehicle.

These and other features and advantages of this invention are describedin, or are apparent from, the following detailed description of variousexemplary embodiments of the systems and methods according to thisinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features of this invention will becomemore apparent and the invention itself will be better understood byreference to the following description of embodiments of the inventiontaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic side elevation view of a combine harvester havinga cooling system incorporating the principles of the present invention,portions of the harvester being broken away to reveal internal detailsof construction;

FIG. 2 is an exploded isometric view of an embodiment of the coolingsystem of the harvester of FIG. 1;

FIG. 3 is a side elevation view of a portion of the cooling system ofFIG. 2;

FIG. 4 is an end view of a portion of the cooling system of FIG. 2;

FIG. 5 is an enlarged end view of a portion of the cooling system ofFIG. 2;

FIG. 6 is a graph of a typical reverse cycle of the cooling system withthe PWM duty cycle on the Y-axis and time on the X-axis; and

FIG. 7 is a graph of the actual speed versus the desired speed whentuning the control system of the cooling system of the harvester.

Corresponding reference characters indicate corresponding partsthroughout the views of the drawings.

DESCRIPTION OF EXAMPLE EMBODIMENTS

The present invention is susceptible of embodiment in many differentforms. While the drawings illustrate and the specification describescertain preferred embodiments of the invention, it is to be understoodthat such disclosure is by way of example only. There is no intent tolimit the principles of the present invention to the particulardisclosed embodiments. References hereinafter made to certaindirections, such as, for example, “front”, “rear”, “left” and “right”,are made as viewed from the rear of the harvester looking forwardly.

The present inventions may be used in any work vehicles such as, forexample, harvester combines, windrowers or other types of agricultural,construction or forestry vehicles. An exemplary combine harvester 10selected for illustration in FIG. 1 has a single rotary flow processingsystem 12 that extends generally parallel with the path of travel of themachine. However, as will be seen, the principles of the presentinvention are not limited to harvesters 10 with processing systems 12designed for rotary flow, nor to axial flow harvesters having only asingle such processing system. However, for the sake of simplicity inexplaining the principles of the present invention, this specificationwill proceed utilizing a single rotary flow processing system 12 as theprimary example.

As well understood by those skilled in the art, in the illustratedembodiment combine harvester 10 includes a harvesting header (not shown)at the front of the machine that delivers collected crop materials tothe front end of a feeder house 14. Such materials are moved upwardlyand rearwardly within feeder house 14 by a conveyer 16 until reaching abeater 18 that rotates about a transverse axis. Beater 18 feeds thematerial upwardly and rearwardly to a rotary processing device, in thisinstance to a rotor 22 having an infeed auger 20 on the front endthereof. Auger 20, in turn, advances the materials axially into theprocessing system 12 for threshing and separating. In other types ofsystems, conveyor 16 may deliver the crop directly to a threshingcylinder.

Generally speaking, the crop materials entering processing system 12move axially and helically therethrough during threshing and separating.During such travel the crop materials are threshed and separated byrotor 22 operating in cooperation with threshing concaves 24 andseparator grate assemblies 26, with the grain escaping laterally throughconcaves 24 and grate assemblies 26 into cleaning mechanism 28. Bulkierstalk and leaf materials are retained by concaves 24 and grateassemblies 26 and are impelled out the rear of processing system 12 andultimately out of the rear of the machine. A blower 30 forms part of thecleaning mechanism 28 and provides a stream of air throughout thecleaning region below processing system 12 and directed out the rear ofthe machine so as to carry lighter chaff particles away from the grainas it migrates downwardly toward the bottom of the machine to a cleangrain auger 32. Auger 32 delivers the clean grain to an elevator (notshown) that elevates the grain to a storage bin 34 on top of themachine, from which it is ultimately unloaded via an unloading spout 36.A returns auger 37 at the bottom of the cleaning region is operable incooperation with other mechanism (not shown) to reintroduce partiallythreshed crop materials into the front of processing system 12 for anadditional pass through the system.

The combine 10 includes a framework around the processing system 12 thatpreferably includes a front bulkhead and a center bulkhead where theconcaves 24 are supported between the front and center bulkheads. Thegrates 26 are preferably supported between the center bulkhead and arear bulkhead. As shown in FIG. 1, both the concaves 24 and grateassemblies 26 together concentrically receive the rotor 22 to serve aspart of processing system 12.

Turning now to FIG. 2, the combine 10 includes a cooling system 50 ofthe present invention. In one or more embodiments of the presentinvention, the cooling system 50 includes one or more air movers 60 suchas a shrouded rotary fan having one or more fan blades 62 surrounded byshroud 63. However, the present invention contemplates other means ofgenerating airflow or moving air from the exterior environmentsurrounding the combine 10 to the cooling system 50 and to the interiorof the combine 10 such as the engine compartment. The air mover 60 isdriven independently from the engine of the combine 10. Preferably, theair mover 60 is driven by a hydraulic motor 64 (FIG. 5). In someembodiments, the air mover 60 is a fan having a substantially verticalaxis of rotation and a substantially horizontal intake face. In someembodiments, the axis of rotation may be off vertical by about 10 to 20degrees. Also, the intake may be off horizontal by about 10 to 20degrees.

Control of the hydraulic motor 64 of the air mover 60 is provided by aproportional hydraulic control valve 66 to permit variable speed and anon/off hydraulic control valve 68 for direction control. When the on/offhydraulic control valve 68 is in the “off” position, the air mover 60operates in the forward direction and when the on/off hydraulic controlvalve 68 is in the “on” position, the air mover 60 operates in thereverse direction. Both hydraulic control values 66, 68 are controlledusing temperature data from heat exchangers/coolers 102, 104, 106, 108of the cooling system as described in greater detail below.

A debris screen 70 may be used overtop of the air mover 60. In suchcase, a cleaning system may be used to remove debris collected on thescreen. However, in the cooling system 50 of the present inventiondefined in greater detail below, it is preferable to have the air mover60 remain free of any such cleaning system.

The cooling system 50 may also comprise a cooling box 80 at leastpartially defined by a plurality of heat exchangers. The cooling box 80may sometimes be referred to as an air box. One or more heat exchangers102, 104, 106, 108 are used to define the cooling box 80. Preferably,one or more air movers 60 provide single pass airflow though the coolingbox 80 in the sense that the air passes through the cooling box 80 once.Upstream faces 92, 94, 96, 98 of the heat exchangers 102, 104, 106, 108cooperate with one another to at least partially define a substantiallyclosed interior of the cooling box 80. The cooling box 80 may alsoinclude opposing end or side walls such as end walls 82, 84. Opposingheat exchangers 102, 104, 106, 108 are arranged or angled in the airflowfrom the air mover 60 relative to one another to define a v-shape.However, in some embodiments, stacked heat exchangers may be utilized.

In one or more embodiments, the air mover 60 is operative to pushambient air downward through the cooling box 80 from overhead of thecombine 10 and to push airflow across the upstream faces 92, 94, 96, 98of heat exchangers 102, 104, 106, 108. Because of the pushed airflowstatic pressure inside the cooling box is greater than the staticpressure outside the cooling box 80. One or more of the heat exchangers102, 104, 106, 108 are positioned in the airflow after an intake face ofthe air mover 60 and before the engine 120. Preferably, the air mover 60is positioned adjacent to and above the cooling box 80 and the heatexchangers 102, 104, 106, 108 are angled in the airflow toward oneanother. The upstream faces 92, 94, 96, 98 of the heat exchangers 102,104, 106, 108 converge in the airflow as the distance from the air mover60 increases. Preferably, opposing proximal ends of the heat exchangers102, 104, 106, 108 in the front of the airflow or closer to the airmover 60 are spaced further apart from one another compared to thespacing between opposing distal ends of the heat exchangers 102, 104,106, 108 further along in the airflow. If the air mover 60 is a rotatingfan, then the upstream faces 92, 94, 96, 98 of the heat exchangers 102,104, 106, 108 are preferably angled relative to an axis of rotation ofthe air mover 60.

In one or more embodiments, heat exchanger 102 is a radiator coupled toan engine and a water pump (not shown) of the combine 12 by acirculation path for controlling the engine's operating temperature withcoolant such as antifreeze. The coolant picks up heat from the engine120. A thermostat (not shown) responds to the temperature of the coolantand opens to allow hot coolant to travel to the heat exchanger 102.

In one or more embodiments, heat exchanger 104 is a charge air cooler(CAC) used to cool engine air after it has passed though a turbochargerbut before it is routed into the intake manifold of the engine. As isknown in the art, air comes in through an air cleaner into theturbocharger where it gains heat and then exits the turbocharger to thecharge air cooler 104 and then goes to the intake manifold of theengine. It is desirable to mange the temperature rise through theturbocharger because when pressurized, the air is heating up. Atemperature difference for the charge air cooler 104 of about 25 C aboveambient temperature is preferable. Ambient temperature may be taken fromthe exterior of the combine 10 or from the temperature of the air in orat the exit of the air filter. Air into the air filter comes throughcooling box 80.

In one or more embodiments, heat exchanger 106 is a hydraulic fan heatexchanger used to transfer heat from hydraulic fluid from the hydraulicmotor 64 driving the air mover 60. Also, heat exchanger 108 may be anoil cooler for other hydraulically driven systems typically found on awork vehicle such as combine 10 or a windrower.

In another embodiment, one of the heat exchangers 102, 104, 106, 108defining the cooling box 80 may be for a hydraulic system independent ofthe combine 10 itself that may be used for an implement towed by thework vehicle. Also, one of the heat exchangers 102, 104, 106, 108 may befor a hydraulic power take off

As perhaps best seen in FIG. 4, the heat exchangers 102, 104, 106, 108are preferably arranged in a v-shaped manner and relative to one anotheras shown herein which depicts the easiest and most cost effective way totransfer heat with the heat exchangers 102, 104, 106, 108 and takes intoaccount the distribution of airflow from the air mover 60. However, theshape of the system 50, the cooling box 80, or the location of each ofthe heat exchangers 102, 104, 106, 108 relative to one another, may bedifferent depending on the particular heat exchangers selected becausefactors such as the depth of the core or how fine the fins easilyaffects the balance of heat rejection with the airflow. Preferably, theairflow is balanced or parallel out each side of the v-shaped coolingbox 80 and a single pass of fresh airflow is pushed across each theupstream faces 92, 94, 96, 98 of the heat exchangers 102, 104, 106, 108defining the inner confines of the cooling box 80. A portion of thefresh airflow brought into the cooling box 80 passes once through one ofthe heat exchangers 102, 104, 106, 108 and each heat exchanger has itsown portion of the airflow from the air mover 60. In other words, eachheat exchanger 102, 104, 106, 108 defining at least a portion of thecooling box 80 receives fresh airflow from the air mover 60 and noportion of the airflow is recirculated through another heat exchanger.Also, a heat exchanger may be referred to as single pass because itsfluid or coolant passes through only once.

However, in some cases an external heat exchanger 110 (FIG. 2), such asa condenser for the AC of the cab of the work vehicle, may be placedoutside of the cooling box 80 and in front of the air mover 60. In suchcase, because the heat exchanger 110 is outside the cooling box 80, theairflow from within the cooling box 80 and across each of the heatexchangers 102, 104, 106, 108 defining a portion of the cooling box 80may still be referred to as single pass airflow. Heating of the airflowfrom the heat exchanger 110 placed in front of the air mover 60 has anominal affect on the temperature of the airflow provided to the coolingbox 80 by the air mover 60 and therefore the airflow is still referredto as fresh air.

As perhaps best seen in FIG. 4, the cooling system 50 may also include adebris passage 130 for passing debris that enters the cooling box 80from the exterior environment along with the airflow generated by theair mover 60. The debris passage 130 is preferably defined between atleast a pair of opposing heat exchangers 102, 104, 106, 108. The debrispassage 130 permits debris to pass from an upper portion of the coolingsystem 50, down between opposing heat exchangers, and to the exterior ofthe cooling system 50 though a debris outlet 134 defined betweenopposing ends of the heat exchangers 102, 104, 106, 108. In oneembodiment, the narrowest spacing between the lowermost or convergingdistal ends of opposing heat exchangers defines an elongated debrisoutlet 134 that substantially corresponds with the horizontal width ofthe heat exchangers 102, 104, 106, 108 and thus the cooling box 80 asbest seen in FIG. 3.

Preferably the debris passage 130 within the cooling box 80 ispositioned underneath and substantially vertically aligned with the airmover 60 and also substantially vertically aligned with the debrisoutlet 134 underneath, so that the most can be made out of gravityassisting in removing the debris from the cooling box 80. Because theair mover 60 is reversible, it provides airflow in one direction whenpushing air into the cooling box 80 and provides airflow in a seconddirection when operated in the reverse direction to draw air out of thecooling box 80. When the air mover 60 is operated in a first directionto push airflow into the cooling box 80, a portion of the airflowescapes through the debris outlet 134 at a greater velocity compared toairflow passing through the heat exchangers 102, 104, 106, 108. Thishigher velocity airflow can be used to facilitate removal or forcedebris from the cooling box 80. When the air mover 60 is operated in thereverse or second direction, the reversed airflow agitates the unwanteddebris that is being held or that may have become stuck within thecooling box 80. Then, when the air mover 60 is returned to operating inthe first direction, the agitated debris then may pass through thedebris outlet 134.

In addition to the cooling system 50 itself described herein, theinvention includes methods for operating one or more air movers 60 tominimize power consumption by having the speed of the air mover 60dependent on cooling requirements. For example, reversing cycles of theair mover 60 may be regulated by allowing a minimum and maximum timebetween reverse cycles. This prevents perpetual reversing conditions,but also forces reverse cycles at regular intervals. The air mover 60may also be reversed when the engine speed is lowered below a minimumthreshold, suggesting a shutdown condition may occur and removing anydebris where it may otherwise reside during idle periods thus allowingadhesion.

In one or more embodiments, a control method senses multiple signals andwhen combined, will control the cooling of the air mover 60 to minimizepower consumption while allowing data from the heat exchangers 102, 104,106, 108 to regulate the speed of the air mover 60 as required. Duringair mover 60 operations, each system with a heat exchanger is evaluatedfor desired air mover speed to maintain temperatures within definedbounds. For example, temperature data for the engine, hydraulic oil, andengine intake manifold are measured. The temperature data results in anassociated required fan speed for cooling each heat exchanger 102, 104,106. The temperature data is reconciled by using the highest air moverspeed (to address the most critical temperature data) as the overallresulting/set point speed. In other words, the highest desired air moverspeed as a result of the temperatures of each of the heat exchangersystems becomes the set point speed for the air mover 60.

At about the same time, the air intake temperature is measured and asuggested speed for the air mover 60 is determined. Empirically, the airmover 60 should be running at the suggested speed to meet equilibriumcooling conditions. The suggested speed is derived using a mathematicalmodel using suggested speed determined as function of the air intaketemperature. If the overall set point speed exceeds the suggested airmover speed, a reversing condition exits suggesting a restricted screen70 or debris within the cooling box 80 preventing proper cooling. Thedetermined set point speed may be automatically compared to thesuggested speed of the air mover 60 to initiate reversing of the airmover 60 as explained below.

Because the air mover 60 is open loop controlled, the cooling system 50must convert the requested speed to a corresponding Pulse WidthModulation (PWM) duty cycle for control of the proportional hydraulicvalve 66. An air mover speed sensor may be used in some embodiments, butis not required because there is a relationship between air mover speedand PWM. The requested air mover speed is converted to a value settingor percentage of maximum voltage. The hydraulics are organized such thata higher duty cycle results in a lower air mover speed. If there is noelectrical power to the air mover 60, the air mover 60 will operate atmaximum RPM in the forward direction because the hydraulics will stilloperate to keep the system cooled as a failsafe to avoid overheating.

One of the features of the present inventions is the multiple conditionsto control the reversing of air flow. One or more air movers 60 may bereversed upon the occurrence of many conditions such as when the setpoint speed exceeds suggested air mover speed from the ambienttemperatures, time exceeds the maximum allowed between reverse cycles,coolant temperatures exceeds critical temperature, hydraulic temperatureexceeds critical temperature, charge air delta temperature rise exceedscritical temperature, user requests a reverse cycle, and reverse cyclewith equipment shutdown. In some instances, as described below, thefrequency at which the airflow reverses may be restricted. Onceconditions return to normal, the reversing of the airflow can bedeactivated.

1. Determined Set Point Speed Exceeds Suggested Air Mover Speed from theAmbient Temperatures

Once the set point air mover speed is determined, the reversingconditions are evaluated. Automatic reversing air mover conditions existwhen the overall resulting speed of the air mover 60 exceeds thesuggested speed. This allows for debris removal using air moverreversing at various ambient temperature conditions. Without the ambientconsiderations, reversing may only occur at extreme temperatures usingcritical reversing conditions described below (critical engine coolant,critical hydraulic oil temperature, and critical charge airtemperature). By conducting an earlier reverse cycle, the air moverconsumes less power by running at slower required speeds and any lodgeddebris on the screen 70 or within the cooling box 80 may be more easilyremoved. As any temperature used to determine the set point increases,the air mover speed increases to compensate, creating further vacuum andlodging debris into the cooler screen 70 or in the cooling box 80. It isdesirable to dislodge the debris before it gets deeply embedded into thescreen 70 or cooling box 80 by reversing the air mover 60.

2. Maximum Allowed Time is Exceeded Between Reverse Cycles

Conditions may exist that would normally prevent the air mover 60 fromreversing. To prevent debris buildup in those conditions, a timedreverse may be implemented. The maximum allowed time between reverseconditions is defined by a stored parameter in the controller such asabout 900 seconds. In some embodiments, a minimum time period couldelapse before consecutive occurrences of reversing the air mover 60 toprevent the air mover being in a constant reverse pattern. This value isalso defined by a stored parameter such as about 120 seconds.

3. Coolant Temperature Exceeds Critical Temperature

If the engine coolant temperature continues to climb and exceeds thecritical temperature set at about 101 C, a reverse request can be sent.Desirably, reverse does not occur until the minimum allowed reversedtime has elapsed.

4. Hydraulic Temperature Exceeds Critical Temperature

In one embodiment, if the hydraulic oil cooler temperature exceeds about85 C, a reverse request is sent. Desirably, reverse of the air mover 60does not occur until the minimum allowed reversed time has elapsed.

5. Charge Air Temperature Rise Exceeds Critical Temperature

If the charge air cooler temperature rise (Intake manifoldtemperature—Intake air temperature (preferably before the charge aircooler)) exceeds about 25 C, a reverse request may be sent. Desirably,reverse of the air mover 60 does not occur until the minimum allowedreversed time has elapsed.

6. User Requested Reverse Cycle

The operator interface of the combine 10 has a button that may bepressed to force an air mover reverse condition. 0

7. Reverse on Shutdown

Because the screen 70 for the cooling box 80 is preferably substantiallyhorizontal on the top of the combine 10, it is desirable to ensure thatall debris is removed when the combine 10 is parked. A reverse requestmay be initiated when the engine RPM was above 1800 RPM and then dropsbelow 1500 RPM suggesting the combine 10 is being parked. Desirably,reverse of the air mover 60 does not occur until the minimum allowedreversed time has elapsed.

Reversing Cycle

When a reverse cycle occurs, in one or more embodiments of the presentinvention, the system may preferably execute the following sequence (anytime or range of time may be a preset and stored configurable value):

Slow the air mover 60 to minimum speed (approximately 70% duty cycle);

Wait approximately 0.1 to 3 seconds for slowing of the air mover 60;

Activate the on/off hydraulic control valve 68;

Speed the air mover 60 (in reverse) up to about 1400 RPM, this is aconfigurable preset value stored in controller memory (fan actually runs1800 RPM when using normal control algorithm, less power is requiredwhen operating in reverse);

Hold for approximately 0.1 to 3 seconds, this is a configurable presetvalue;

Slow the air mover 60 to minimum speed;

Wait about 0.1 to 3 seconds for slowing, this is a configurable presetvalue;

De-activate the on/off hydraulic control valve 68;

Resume normal control algorithm.

Speed of the air mover 60 desirably is changed at a constant rate. Thegraph in FIG. 6 shows a typical reverse cycle. The PWM duty cycle is onthe Y-axis and time on the X-axis. Higher PWM values results in slowerair mover speed.

Tuning

The air mover control algorithm allows flexibility for tuning There areseveral equations in the system to set requested speeds, suggestedspeeds and duty cycles. The relationship between air mover speed andtemperature is not linear but within the bounds of where the systems ofthe combine 10 operate it may be preferable to approximate it as alinear system.

Duty Cycle

Because the control system uses air mover speed for the controlalgorithm and air mover speed may not be measured, a relationshipbetween air mover speed and value setting must exist. This is achievedby a tuning process. The control system has two fixed PWM values (70%and 0%) corresponding to minimum and maximum speed, respectively. Theactual air mover speed is recorded for those values. Initial speedvalues for 0% and 70% were tried based upon manual air mover speed testsand the result revealed the air mover did not track to actual speed.Values of 2700 and 657 worked closer, but the values of 2650 and 657appeared to provide the best approximation. FIG. 7 reveals thenon-linearity in the PWM versus Speed settings. The 2650/657 actuallyworks well because when more cooling capacity is required, the air moveris running slightly faster than the theoretical speed.

Intake Air Temperature

Intake air temperature is a good approximation to ambient airtemperature. The intake air temperature sensor may be installed inproximity of the air filter/cleaner or is typically installedapproximately ⅓ of the distance between the air cleaner and theturbocharger inlet, in a metal tube. To the extent a sensor isreferenced throughout this document, it is any sensor that convertstemperature into a measurable electrical signal. Test results (using anindependent temperature sensor), reveal the true intake air temperatureis approximately 5-6 C greater than the ambient temperature once thesystem reaches operating conditions. This is understandable consideringthe intake air source comes from the interior of cooling package 50.

The combine intake air sensor may be about 6 C higher than the intakeair temperature once hot conditions occurred because the sensor does notonly measure intake air temperature. It is biased with conductivetemperatures belonging to its surroundings. A bias may be imposed on theair intake sensor to compensate for any thermal conductivity or solargain the sensor may pickup. Because this appears to be a fixed bias atall times, the air mover control algorithm preferably subtracts about 6C (i.e. an offset temperature) from the actual intake air temp sensorand establishes this as the intake air temperature. In cold or startupconditions, the combine intake air temperature will reveal this negativebias. However, it takes a very short period to mitigate this.

Speeds and Times

There are various air mover speeds and times that are adjustable withone or more software modules. For example, when the engine is at lowidle (high idle is about 1500 RPM or more, but the vehicle is notmoving), the air mover speed can be dropped to conserve power.Preferably, air mover speed is controlled as a function of time so thatspeed changes are smoothed over time and not as a step change to controlnoise. The resulting values are used to reduce noise emissions forbetter operator and bystander noise comfort:

At approximately 975 RPM—Minimum air mover speed at low idle

1300—Minimum air mover speed at high idle (>1500 RPM)

1400—reverse air mover speed (air mover true speed is approximately 1800owing to reduce power requirements in reverse)

657—Minimum air mover speed at 70% (for PWM tuning)

2650—Maximum air mover speed at 0% (for PWM tuning)

3 seconds—reverse time

1 second—Slowdown time

1 second—valve delay

EXAMPLES

Engine Radiator Restricted/Blocked with Debris

As power requirements increased, the charge air cooler (CAC) temperatureinitially controls the cooling air mover requirements beginning atapproximately 165 seconds. CAC continues to control the air mover untilabout 300 seconds, when the coolant temperature takes control. As thecooling requirements increase due to the blocked radiator, the speed ofthe air mover 60 responds accordingly.

The first reverse cycle occurs at about 400 seconds. This cycle occursbecause the requested air mover speed (from the engine cooler), exceedsthe suggested air mover speed based on the intake air temperature.Further reverse cycles occur at the maximum allowed frequency of 120seconds. All would be initiated with the requested speed exceeding thesuggested air mover speed given the ambient conditions. If thetemperature of the engine 120 exceeds the critical reverse temperatureof 101 C, the air mover may be reversed just prior to reaching thiscritical temperature, preventing further reverses until the minimumallowed time has elapsed. The engine loading was reduced at 1156seconds, reducing the cooling requirements.

Charge Air Cooler (CAC) Restricted/Blocked with Debris

Restricting or blocking the charge air cooler with debris results inrapid air mover speed increase, resulting is the charge air driving theair mover speed. The reverse cycle is initiated by an increase in thecoolant temperature above the desired ambient temperature speed.Reversing occurs at the maximum allowed time of 120 seconds to mitigatethe increased charge air temperature delta. The maximum allowed CACdelta temp of >25 C causes the reverse cycles. The intake airtemperature continues to increase over time until it reaches a plateauof approximately 48 C. With the increase in intake air temperature, theintake manifold temperature also increases. By the 6^(th) reverse cycle(approx 700 seconds), the charge air delta temperature is such that theair mover may begin to run slightly slower (approximately 100 rpm) dueto a lower CAC delta temperature. The next reverse cycle is triggered bythe >25 C CAC delta temperature, and after that, the intake airtemperature increases enough that a subsequent reverse cycle is notinitiated.

Supplemental Cooling Synchronization

One or more embodiments of the present invention include a controlmethod to operate a supplemental cooling system 50A for independenthydraulic systems such as a towed implement or hydraulic PTO. An airmover 60A of the optional supplemental air cooler system 50A maycomprise one or more supplemental air movers 60A, such as a series ofelectric or hydraulic fans, and be synchronized with the primary coolingair mover 60 and their reversing ability combined. The second airflowmay be used exclusively for systems independent of the combine 10 butmay instead be used to cool hydraulics for a supplemental power sourcefor the work vehicle such as an additional hydraulic pump for a combineheader requiring supplemental cooling. The second airflow could also beused for the systems independent of the combine 10 in combination withthe supplemental power sources of the work vehicle. Synchronizing thereversing of both air movers systems 60, 60A is preferable because ifeach system reversed independent of the other one air mover system whenreversed would dislodge debris that would be drawn in by the other airmover system.

Staged air movers reduce power consumption to those times when onlynecessary. The method includes turning on one or more of the air movers60A as the heat rejection load is required. The method may also includethe step of comparing cooler output temperatures of the hydraulic oilcooler to oil reservoir temperatures and implement an air moverreversing operation to clear a supplemental cooling box screen 70A orclear the inner confines of the supple mental cooling box 80A fromdebris accumulation. The supplemental air mover 60A may be positioned atthe left rear engine deck of the combine 10.

Temperatures are measured for the hydraulic oil reservoir of the combine10 and at the output of the supplementary cooler 80A. Staging of the airmovers 60A is controlled by absolute cooler outlet temperatures. Forexample if three air movers 60A are installed for cooling in a linearsetup, a three stage implementation may be used where stage one would bethe center air mover, stage two would be the two outside air movers, andstage three would be all air movers operational. The stages wouldincrease as the outlet temperature increase.

Reversing of the air movers 60A is required to remove debris from thesupplemental cooler. There may be several reversing criteria such asmanual reverse, timed reverse, temperature reverse, synchronizedreverse, and shutdown reverse. When reversing occurs, all presentlyoperating air movers are stopped of forward motion and all air moversare reversed after a small delay. If possible, the air movers arestarted sequentially to minimize the startup currents associated withelectric motors.

Manual reverse may be initiated by the operator. Timed reverse is basedon a fixed period of time. Temperature reverse is when the supplementarycooler 80A does not cool the oil to within a fixed delta temperaturewhen compared to the hydraulic oil reservoir. Synchronized reverse iswhen reversing occurs at the same time as the primary cooler 80.Shutdown reverse occurs after the optional system has ceased operatingand the cooler has reduced the outlet temperature to within a fixeddelta temperature of the reservoir.

One or more embodiments of the present invention include a method fordetermining when a cooling system 50 is restricted with debris bymeasuring the performance of heat exchangers individually. The methoduses temperature sensors to measure the temperature at the inlet and atthe outlet of the airflow on both sides a particular heat exchanger. Aninitial or baseline temperature difference is determined when the heatexchanger is substantially unrestricted. Preferably, the air mover isfirst reversed to allow the initial temperature difference to bedetermined immediately thereafter or at some later point in time. Thisinitial temperature difference is representative of the heat exchangersperformance when airflow through the heat exchanger is maximized for agiven air mover speed or CFM of airflow. As airflow through the heatexchanger is restricted by debris, the difference in temperature betweenthe inlet airflow and the outlet airflow will diminish. As time passes,debris buildup causes the temperature difference to drop. Once thetemperature difference reaches a predetermined value less than theinitial temperature difference a reverse cycle is signaled.

A method for removing debris based on the performance of an individualheat exchanger includes the step of providing airflow to cool the heatexchanger. The method includes the steps of determining a temperature ofthe airflow at an inlet to the heat exchanger and determining atemperature of the airflow at an outlet of the heat exchanger. Then, themethod may include determining a temperature difference between theinlet and outlet temperatures of the heat exchanger. Preferably thistemperature difference is determined after a period of time after aninitializing reverse but while the heat exchanger is performingoptimally. After determining that the temperature difference isdecreasing over time; the method includes reversing direction of theairflow to remove debris from the heat exchanger.

The method may also include the step of performing an initializingreverse of the airflow prior to determining the temperature differencerepresentative of when the airflow through the heat exchanger ismaximized. The method may also include the step of waiting to reversethe airflow until the temperature difference reaches a predeterminedvalue less than the temperature difference that had been determined whenthe airflow through the heat exchanger had been maximized. Preferablythe temperatures and the temperatures are determined based on a specificCFM of airflow or when an air mover is operating at a specific speed.

The method for removing debris based on the performance of an individualheat exchanger may comprise the steps of providing airflow to cool theheat exchanger, determining a first temperature difference between aninlet and an outlet of the heat exchanger when airflow though the heatexchanger is substantially unrestricted, determining a subsequenttemperature difference between the inlet and the outlet of the heatexchanger, determining the subsequent temperature difference is lessthan the first temperature difference by a predetermined amount; and inresponse to determining the subsequent temperature difference is lessthan the first temperature difference by the predetermined amount,reversing direction of the airflow to remove debris from the heatexchanger.

The foregoing has broadly outlined some of the more pertinent aspectsand features of the present invention. These should be construed to bemerely illustrative of some of the more prominent features andapplications of the invention. Other beneficial results can be obtainedby applying the disclosed information in a different manner or bymodifying the disclosed embodiments. Accordingly, other aspects and amore comprehensive understanding of the invention may be obtained byreferring to the detailed description of the exemplary embodiments takenin conjunction with the accompanying drawings, in addition to the scopeof the invention defined by the claims.

What is claimed is:
 1. An air cooling system for a vehicle having anengine, comprising: a cooling box having an interior at least partiallydefined by upstream faces of a plurality of heat exchangers, with atleast two of said plurality of heat exchangers on a first side of thecooling box and at least one of said plurality of heat exchangers on anopposing side of said cooling box, each of said plurality of heatexchangers providing cooling to a different component of the vehicle,wherein opposing heat exchangers are angled relative to one another withproximal ends of opposing heat exchangers spaced further apart thandistal ends of said opposing exchangers such that said heat exchangerscooperate with one another to define a v-shape; and an air moveroperative to push ambient air downward into said cooling box fromoverhead of the vehicle, said air mover comprising a rotating fan havinga substantially vertical axis of rotation, wherein said upstream facesof said heat exchangers are angled relative to an intake face of saidair mover and are angled relative to said axis of rotation of said airmover so as to push airflow across said upstream faces.
 2. The coolingsystem of claim 1 wherein said heat exchangers are positioned in saidairflow after said air mover and before the engine.
 3. The coolingsystem of claim 1 wherein said air mover is driven independentlyrelative the engine of the work vehicle.
 4. The cooling system of claim1 further comprising a debris passage defined between distal ends ofheat exchangers on opposing sides of said cooling box, said debrispassage for passing debris to the exterior of said cooling system. 5.The cooling system of claim 1 wherein said debris passage permits debrisfrom to fall between opposing heat exchangers to the exterior of saidcooling system.